Auto Express did a test a while ago (and I think a subsequent campaign) showing that tyre performance falls off quite dramatically when the tread depth drops below 3mm. They were trying to get the government to up the min tread depth to 3mm.

In very poor weather, it probably makes a difference if you end up in an emergency situation. In most other conditions it probably makes no difference.

What is your reason for changing them? You mention 1000 miles.
Are you concerned that the tyre will wear down to the legal limit before the end of your trip?
Or that your safety may be compromised as a result of the relatively low tread depth.

If it's the first one, then you should be OK unless on really soft rubber and doing lots of traffic light grand prix starts.
If it's the second one, then it's something only you can really answer. If you can afford it and would feel more confident on new rubber, then get them changed.

Personally, I wouldn't bother. Perhaps if it was coming into winter, but not at this time of year.

What are the rear tyres like? Is your car front or rear wheel drive?
In Scotland unless you're very lucky you'll get some rain so you'll need lots of grip and good rain clearing channels to prevent aquaplaning.

I personally replace mine at about 3mm to cover the changeable weather situations.

This.
Some of the biggest accidents in the Beatock area of the M74 are caused by aqua planing The standing water on the new section between Carlisle/Gretna also suffers from horrendous surface water.
All depends on how good you think you are at avoiding other idiots on the road, there are plenty
Changed my 2 fronts for that very reason a few weeks ago, 2wks of caravanning.

"Type shops specifically recommend against this nowadays,"
1st place i would go for advice- ref kwikfit thread.

"it's best to have the grip on the rear if anywhere,"
Say that to yourself out loud.
FWD which is what we are talking about, you ask the front wheels pull you along, steer you and stop you.
But you'd rather have more grip on the draggers on the back!

"to stop any lift off oversteer occurring. Under steer at the frontis usually safer"
One circumstance where good rear grip helps, however this is a all a lawyers construct. i can see how poor driving practice could lead you into this situation, but how many times a year do you incounter lift off over steer?
Against stopping slowing or steering away from someone else.

It's a topic that seems inexplicably entrenched, this. I can see the logic but like Speshpaul I don't find it worked in practice (in my experience, on my cars, ymmv). Even with downright crap tyres on the back both my cars pushed the front first, I never had the rear slide without the front already being lost, so making front end slides more common and more dangerous in order to make vanishingly rare rear slides safer didn't make any sense. The rear just has a much easier job to do and so needs less grip to do it.

Or to put it another way... The objective isn't to decide which way you go through the hedge; It's to stay out of the hedge entirely.

haha very good. They may have crashed, or just had a scary moment on a roundabout, however from your description they turned backwards as the rear end got lary instead of the front pushing on. Not disputing that they made an arse of something to kick the whole incident off.

"it's best to have the grip on the rear if anywhere,"
Say that to yourself out loud.
FWD which is what we are talking about, you ask the front wheels pull you along, steer you and stop you.
But you'd rather have more grip on the draggers on the back!

What all the major tyre manufacturers recommend, is more grip on the back. Maybe they know something about tyres and grip and whatnot.

Northwind - Member
It's a topic that seems inexplicably entrenched, this. I can see the logic but like Speshpaul I don't find it worked in practice (in my experience, on my cars, ymmv). Even with downright crap tyres on the back both my cars pushed the front first, I never had the rear slide without the front already being lost, so making front end slides more common and more dangerous in order to make vanishingly rare rear slides safer didn't make any sense. The rear just has a much easier job to do and so needs less grip to do it.

I've managed to do this - not through trying, so I now make sure that my tyres with the most grip are on the back...

When I got my car the fronts were almost bald, so I asked the bloke to get them changed or knock £150 off the cost of the car He of course changed them for the cheapest tyre he could get (£35 each for 205/45/16s - Formula 2000's I think they were called).
Put up with them and when the rears needed changing I got some Kumho Ecsta Sports put on. Asked the garage to put them on the front and swap the rubbish fronts to the rear.
Few nights later driving to the gym in the rain and had to go right at a roundabout; the fronts tracked round perfectly fine. I wasn't going fast for the roundabout, but the backend all of a sudden started coming round (which was an odd sensation in a FWD car). I managed to catch it and carry on, but got the rears swapped that weekend for the same tyres as I'd just had put on the front.

I'd rather provoke understeer in a FWD car, as that is what you expect to happen and what the car is set-up to do.

Having just bought two new tyres - which are to replace worn fronts I've just read this on the kwik fit website so although its counter intuitive I guess it makes sense.

In the unlikely event that a tyre deflates suddenly, then it is easier to control the vehicle if this occurs at the front of the vehicle. For improved handling and stability it is now recommended that the ‘best’ tyres should always be fitted at the rear of the vehicle. This is irrespective of whether the car is front or rear wheel drive.

stumpy01- so you had nice new tyres on the front and cheap hard as nails tyres on the back that were worn out. Yea.
then you drove to the feed back the front tyres gave you rather that the condition that you knew the rear tyres were in. And it went wrong.

Now you could argue that this is reason to put the new tyres on the back (and the tyre makers lawyers will- see above lawyers contruct.)
Or you could take the info you have - i've got crap tyres on the back. i'm must remember that i'm not Stirling Moss. and drive accordingly.

New on the back is do with protecting tyre makers/suppliers from law suits.

Speshpaul....you are making the assumption that I was 'driving like Stirling Moss'.
As I said in my post, I wasn't driving fast. Just going round that roundabout as I have done many times before without issue.

The thing is, I expect my car to understeer if it is going to lose traction. I don't expect it to oversteer. If I'd have had the same tyres front and rear, then even if the rears were worn it probably wouldn't have happened. But, that's largely irrelevant as it did happen with that set up.
Personally, I'd rather my fwd car understeered. You can do what you want...

Oddly I was thinking that last week as like the OP im down to about 2-3 mm.

Now that the EU has stickers on the tyres showing wet braking and rolling resistance I was a bit surprised to see that STW's mantra that they were no worse on fuel and better than normal tyres even at normal UK temperatures, that they were all consistently scoring the rock bottom marks, where even the crap budget tyres were rating arround a C!